Search for η → e⁺e⁻ decay with the WASA experiment

National Centre for Nuclear Research, Warsaw, Poland

^a e-mail: Marcin.Berlowski@fuw.edu.pl

Abstract

Nowadays the field of searching for a new physics became a very interesting subject in a light meson decays due to a recent results from KTeV collaboration which found the 3.3σ disagreement between Standard Model theory and their results of π^◦ → e⁺e⁻ branching ratio measurement [1]. They propose to explain this discrepancy with a new U boson particle that interacts both with meson and virtual photon producing e⁺e ⁻pair [2]. The same effect could be observed in eta meson decay into electron-positron. The current branching ratio limit [3,4] is far away from the predicted non-Standard Model theory and due to that fact it cannot distinguish between Standard Model and more exotic explanation. The following report shows the analysis highlights for searching for a such effect in pp → pp(η → e⁺e⁻) at 1.4 GeV produced in WASA@COSY experiment.